Martin Delany was a radical pre-Civil War abolitionist, black nationalist, explorer of Africa, and veteran of the American Civil War. His father was a slave, and all four of his grandparents had been captured in Africa and brought to America as slaves, but his mother was free, and by law this meant Delany was born free. From earliest childhood, he was told by his parents that his ancestors were African royalty. His family fled north when his mother faced prosecution for educating her children.

From 1843-47, Delany published Mystery, a weekly newspaper advocating abolition, with Frederick Douglass eventually joining the efforts. Delany then closed Mystery and became co-editor of Douglass's newspaper, North Star. He apprenticed under several physicians in the Pittsburgh area, then opened his own practice, specializing in dentistry and leech therapy. With letters from 17 local doctors attesting to his skill, he applied to several medical schools but was rejected on account of his color, before being admitted at Harvard in 1849. He attended for only a few months, however, before his presence became so controversial that the Dean of the Medical School, Oliver Wendell Holmes, rescinded Delany's admission.

Returning to Pittsburgh, he expanded his medical practice to include women's and children's diseases, and became deeply involved in the Underground Railroad and abolitionist movement. Addressing an 1850 rally, Delany said, "My house is my castle. If any man approaches that house in search of a slave... if he crosses the threshold of my door, and I do not lay him a lifeless corpse at my feet, I hope the grave may refuse my body a resting place, and righteous Heaven my spirit a home."

His 1852 book, The Condition, Elevation, Emigration, and Destiny of the Colored People of the United States, Politically Considered, was the first widely-read call for black nationalism. His novel, Blake, or The Huts of America, was written as something of a response to Harriet Beecher Stowe's novel Uncle Tom's Cabin, as Delany was frustrated by Stowe's portrayal of black slaves as passive victims. One of the first black-authored novels to be published in America, Blake was based on Delany's own underground activities and stories told by friends who had been slaves, and it is seen as a generally accurate portrayal of insurrectionist efforts within slave communities.

Delany helped organize the National Emigration Convention of Colored People, held in Cleveland in August 1854, where he called for abolition, and for free blacks to resettle in the Caribbean, Central or South America, or East Africa. In 1858 he led an expedition to Africa's Niger Valley, where he negotiated treaties with several tribes as a first step for resettlement of American blacks. He then traveled to London, where he spent several months lecturing to scientific groups about his two years in Africa, and to human rights groups about his life in America. In 1861 he addressed a colony of fugitive slaves and American Negro expatriates in Canada. During the Civil War he was assigned to the 104th Colored unit, and became the first African-American to reach the rank of Major in the US Army.

After the war he worked at the Freedman's Bureau, seeking to secure voting rights for former slaves. Settling in South Carolina, he ran for Lieutenant Governor in 1874, losing narrowly, on the ticket of the Radical Independent Republican Party, a short-lived party formed to oppose the Republican Party. In the next election cycle he endorsed the Democrats' ticket, and after the Democrats' victory he was appointed to a judgeship. He was a Fellow of the Royal Society, and active in the Masonic fraternity.

Author of books:The Condition, Elevation, Emigration, and Destiny of the Colored People of the United States, Politically Considered (1852)Blake, or The Huts of America (1859, novel)The Official Report of the Niger Valley Exploring Party (1861, with Robert Campbell)Principia of Ethnology: The Origin of Races and Color (1879)